(1) Field of the Invention
The present invention relates to a warning system for an outboard motor, and more detailedly relates to a warning system in an outboard motor for warning of the occurrence of an abnormal oil pressure.
(2) Description of the Prior Art
Conventionally, in an outboard motor having a four-cycle engine, if an abnormal reduction in oil pressure occurs, an oil-pressure switch detects this anomaly so as to perform engine speed control and/or oil pressure warning control. For example, when oil-pressure reduction occurs at an engine speed equal to or above a certain fixed rate, the engine speed is controlled together with buzzing sound warning, LED lighting etc. On the other hand, when the engine speed is lower than the fixed rate, only the buzzing sound warning, LED lighting etc. are performed.
In the above conventional outboard motor, however, only a single oil-pressure switch is usually used, to merely judge whether the oil pressure exceeds a fixed reference oil pressure. Therefore, it has been impossible to perform detection with consideration of change in oil temperature, posing a problem of an insufficiency of the warning function.
For this reason, two oil-pressure switches having different reference oil-pressure thresholds have been used or an oil-pressure sensor capable of continuously detecting the oil-pressure value has been used. In these cases, however, the oil-pressure switches, oil-pressure sensor and the like are costly, and the controller for processing the thus detected value and controlling the operation based thereon also are expensive, resulting in increase in cost of the whole system.